Scientists have discovered the world's oldest animal sperm inside a tiny crustacean trapped in amber around 100 million years ago in Myanmar. They predict that the animals copulated just before their entrapment in the piece of amber (tree resin), which formed in the Cretaceous period, about 100 million years ago.
The researchers noted that fossilised sperm is exceptionally rare with previously oldest known examples being only 17 million years old.
The study, published in the journal Royal Society Proceedings B, also has implications for understanding the evolutionary history of an unusual mode of sexual reproduction involving 'giant sperm.'